The 31-year-old Wilson, an All-Star in 2004, becomes Seattle's third everyday shortstop this season.

"This was an opportunity for us to acquire a veteran shortstop, a former All-Star player, with leadership qualities and above-average defensive skills," Mariners general manager Jack Zdurienick said. "As we move forward over the next few years it is nice to know that we have solidified the shortstop position."

The Mariners also think Snell can restart his stalled career. The 27-year-old Snell had a 0.96 ERA in six starts with Triple-A Indianapolis, after starting the season 2-8 with a 5.36 ERA in 15 starts for Pittsburgh.

Zdurienick called Snell "a talented pitcher with major league experience who now has an opportunity restart his career after a very successful reassignment in Indianapolis."

Seattle had acquired Cedeno in the offseason from the Chicago Cubs. He struggled after the Mariners gave him their shortstop job this month by trading Yuniesky Betancourt to Kansas City. Cedeno is hitless in his last 26 at bats and is batting .167 in 59 games. The 26-year-old's contract ends after this season.

In Clement, the Pirates are getting the third overall draft pick in 2005 who has shown impressive power but has been unable to catch consistently. He has played first base while being primary a DH at Triple A. Clement, who turns 26 next month, batted .237 with seven home runs in 75 games for Seattle in 2007 and '08. He was batting .288 with 14 home runs and 68 RBIs in 92 games for Tacoma this season.

The Pirates also get minor league right-handed pitchers Nathan Adcock, Brett Lorin and Aaron Pribanic.